The Canadian dollar is hitting another new 5-year low this morning following the Bank of Canada's decision to maintain its benchmark interest rate at 1%.

"Although the fundamental drivers of growth and future inflation appear to be strengthening, inflation is expected to remain well below target for some time, and therefore the downside risks to inflation have grown in importance," said the Bank in a statement, causing traders to push the loonie lower to reflect greater chances of additional easing ahead.

"Today the BoC has told the market in multiple ways that CAD weakness is desirable and the market should keep pushing on an open door," says Alan Ruskin, global head of G-10 FX strategy at Deutsche Bank.

The move in the U.S. dollar-Canadian dollar exchange rate today is sizable — USD is up 0.8% against CAD — but CAD has lurched lower in several sessions since the turn of the new year on this theme, and USD is already up more than 4% against CAD in the year to date.

Société Générale senior forex strategist Sebastien Galy hints that the environment is similar to that in which the U.S. dollar shot upward against the Japanese yen last year as expectations built for a substantial monetary easing campaign there.

"USD/CAD is one the main trending currencies with TRY technically, and from a modeling perspective in a break of regime, which is the complicated way of saying it no longer trades as it used to for many years," says Galy. "This makes standard regression-based valuation metrics obsolete as they will largely follow spot as happened with USD/JPY under Abenomics."

The chart below shows how much speculators have already piled into the trade. The net position of futures traders at the Chicago Mercantile Exchange is one of the largest shorts in years.